There have been a number of attempts to make conductive fabric so that conductive clothing or luggage and the like can be produced into which can be incorporated electronic equipment such as smartphones, GPS devices and personal computers. Such devices have various uses in the consumer, business and military fields.
Traditional methods for making conductive fabrics rely on the inclusion of a conductive filament into the body of the fabric when the fabric is woven.
The first conductive fabric was made of silk organza where the conductive fibre was made of a silk thread wrapped in thin copper foil (E. R. Post and M. Orth, IEEE International Symposium on Wearable Computers, Oct. 13-14, 1997).
Co-weaving of metal wires or conductive polymer filaments within the fabric has also been used (H.-C. Chen, K.-C. Lee and J.-H. Lin, Composites, Part A, 35, 1249-1256, 2004). However, it is difficult to form anything other than the simplest designs from these processes.
Another way of making conductive fabrics is by using conductive polymers. Conductive polymers are widely used for textile coating, including polyaniline and polypyrrole (J. Molina, A. I. del Rio, J. Bonastre and F. Cases, Eur. Polym. J., 45, 1302, 2009 and B. Yue, C. Wang, X. Ding and G. G. Wallace, Electrochim. Acta, 68, 18-24, 2012). However, these polymers do not tend to be as conductive as metals.
A nylon fabric coated in silver is sold under the Shieldex trade mark by Shieldex Trading, Inc. This product uses thick silver and is expensive, and is not offered in a form to make circuits.
WO 2008/133672 (Drexel University) discloses a method of grafting multi-walled nanotubes onto the outer surface of a polyacrylonitrile nanofibre by using a polyelectrolyte as a linker group. No example of any other grafting method is given.
US 2007/0054577 (Avloni) discloses the formation of electroconductive fibres by means of (i) plasma pretreatment followed by (ii) layer-by-layer attachment of a conductive coating using a polyelectrolyte as a linker group.
CN 102120043 (Basic Medical) discloses the attachment of a nanosilver layer to a gauze by using chitosan as a linker in order to impart biocidal properties to the gauze.
WO 00/49219 (Foxwood Research Limited) also discloses a method of coating a substrate with biocidal nanosilver by using chitosan as a linker group to bind the silver particles to the substrate. The chitosan needs to be cross-linked in order to render it insoluble at acidic pH.